scholarly journals Long term effects of withholding phosphate application on North Island hill country: Te Kuiti

1990 ◽  
pp. 21-24 ◽  
Author(s):  
M.B. O'Connor ◽  
C.E. Smart ◽  
S.F. Ledgard
Keyword(s):  
Research Area ◽  
Dominant Factor ◽  
Soil Test ◽  
Stocking Rate ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Noticeable Increase

A farmlet grazing trial at the Te Kuiti Research Area (20 km south of Te Kuiti) began in April 1983 to study the effects on production of reducing or withholding fertiliser over a 6-year period. The effects of withholding fertiliser are considered in this paper. The soils on which the trial was conducted are Mahoenui or Mangatea silt loams typical of 1.3 million ha of North Island hill country. Applications of 250 kg/ha/annum of superphosphate had been applied for 10 years before the trial began, leading to Olsen P tests of 14. In spite of moderate soil test levels, declines in both animal and pasture production where fertiliser was withheld were evident from year 2. By years 3-4 onwards, production declines of some 20-30% were evident. Effects on pasture composition where fertiliser was withheld were evident, with less white clover and more moss and weeds. No noticeable increase in scrub weeds or brush weeds occurred. Maintaining a high stocking rate (or stock pressure) was considered a dominant factor in this regard. Keywords grazing trial, fertiliser, hill country, phosphate, animal production, pasture production

scholarly journals SOIL FERTILITY AND HILL COUNTRY PRODUCTION

1982 ◽  
pp. 153-160 ◽  
Author(s):  
M.G. Lambert ◽  
P.C. Luscombe ◽  
D.A. Clark
Keyword(s):  
Summer Rainfall ◽  
Research Area ◽  
Grazing Management ◽  
Low Fertility ◽  
N Availability ◽  
Stocking Rate ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Legume Growth

Soil, pasture and animal responses to 2 levels of superphosphate were measured within a farmlet trial, at Ballantrae hill country research area, near Woodville, during 1975-80. Soil and pasture measurements were also made for 3 years before the trial started. Pastures, which were dominated by low-fertility-tolerant grasses (LFTC;), moss and flatweeds, were oversown with 4 legumes before the trial started. Soil Olsen P level was 5 under untopdressed pasture in 1973, and 9 in 1975 after application of 500 kg/ ha superphosphate. Superphosphate rates were 120 (on low fertiliser areas q LF) and 640 (on high fertiliser areas = HF) kg/ ha/ yr average during 1975/80. Annual pasture production (adjusted for variable summer rainfall) was 7.1 t DM/ ha from untopdressed pasture and 8.1 t following 500 kg superphosphate/ ha in 1973-74. LF production rose to 8.5, and HF to 12.0, in 1980. Legume contribution rose from 5% in untopdressed pasture to 18% and 23% in LF and HF respectively in 1975/76. By 1979/80 legume contribution had steadily declined to 10% on both treatments, probably due to a measured increase in soil N availability and increased competitiveness of associated grasses. Ryegrass content rose at both fertiliser levels, while LFTG content fell; these trends were greatest under HF. Winter stocking rate was increased from 6 to 10.9 and 14.9 su/ha on LF and HF-respectively. Per animal performance did not decrease. A range of techniques which could increase efficiency of superphosphate use in hill country is discussed. These techniques include: selective application to responsive pastures; spring application; grazing management to encourage legume growth.

scholarly journals Long term (?) effects of withholding superphosphate application on North Island hill country: a 10-year update

1999 ◽  
pp. 63-68 ◽  
Author(s):  
M.B. Dodd ◽  
S.F. Ledgard
Keyword(s):  
Species Composition ◽  
White Clover ◽  
Low Fertility ◽  
Botanical Composition ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Over Time

Measurements of soil phosphate, pasture production and botanical composition from two superphosphate fertiliser trials in northern North Island hill country (Whatawhata and Te Kuiti) have been made over a 15-year period. The impacts of superphosphate fertiliser withholding have included a decline in Olsen P, decreases in annual pasture production of 10-17% (Whatawhata) and 22-42% (Te Kuiti), decreases in the abundance of productive and desirable species (15-20% for ryegrass and white clover), and increases in the abundance of undesirable species (browntop and other low fertility grasses). These changes have increased over time, beyond that period covered by the original experiments (4-6 years). Different responses to withholding between the two sites are still apparent, and the reasons for these are explored. It is not clear that these systems have yet reached a new equilibrium, nor how long it will take for this to happen. The implications for our view of longterm grassland studies are discussed. Keywords: fertiliser, long-term, pasture production, pasture species composition

Long term effects of withholding phosphate application on North Island hill country: Whatawhata Research Centre

1990 ◽  
pp. 11-16
Author(s):  
A. G.Gillingham S. Richardson ◽  
I.L. Power ◽  
J. Riley
Keyword(s):  
Large Scale ◽  
Soil Depth ◽  
Residual Effects ◽  
Research Centre ◽  
Total Production ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Fertiliser Application

From June 1984 to May 1988 a large-scale grazing trial at Whatawhata Research Centre evaluated the effects of a halt to previous superphosphate fertiliser application on hill country production. Over the 4-years pasture production, pasture species composition, stock grazing days or Olsen P soil fertility status were little affected as a result of halting topdressing. Pasture production declined most on 'easy' ( lo-20° slope) slopes after a halt to fertiliser application. The decline was greatest (lo- 13 %) where previous rates of fertiliser had been high. Total production on 'steep' (30~40° slope) slopes did not decline significantly. However, at soil test (Olsen P) levels of less than 10 the pasture moss and dead matter content increased, indicating a deterioration in pasture quality. Legume content did not decline. Within the range of normal topdressing rates to hill country (O-30 kg P/ha/yr) Olsen P tests did not reflect topdressing differences or any effects of a halt to fertiliser application. At higher topdressing rates (50-100 kg Plhalyr) the effect of continued or discontinued topdressing was reflected predominantly in the O-3 cm soil depth. A halt to previous topdressing significantly reduced available grazing over the final 3 years. This decline reflected the decline in measured pasture production. Keywords Phosphate, fertiliser, hill country, residual effects

scholarly journals Long term effects of withholding phosphate application on North Island hill country: Ballantrae

1990 ◽  
pp. 25-28 ◽  
Author(s):  
M.G. Lambert ◽  
D.A. Clark ◽  
A.D. Mackay
Keyword(s):  
Residual Activity ◽  
Annual Rainfall ◽  
Research Station ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Phosphate Retention ◽  
Reactive Phosphate Rock ◽  
Average Annual Rainfall

In a farmlet grazing trial at DSIR's Ballantrae Hill Country Research Station near Woodville the effect of withholding phosphate application was investigated. Soils are yellow-brown earths and related steepland soils with low phosphate retention, and average annual rainfall is 1200 mm. Four 10 ha farmlets, 2 each with histories of high (HF) or low (LF) superphosphate application, had annual applications continued at 125 (LF-LF) or 375 (HFHF) kg/ha; or discontinued on one farmlet in each case (LF-NF and HF-NF), starting in 1981. Soil Olsen P level decreased on the HF-NF area, but not on LF-NF and pasture production decreased by 4.6 and 1.7% p.a. respectively. Botanical composition was affected only on the HF-NF farmlet. Ewes were lighter as a result of not applying fertiliser. Ewe and lamb wool production, and lamb liveweight, were reduced by an average 1.2, 3.7 and 2.6% p.a., respectively, over the 7 years. A phosphate application trial suggested that reactive phosphate rock was as effective as superphosphate in stimulating legume responses in the 1st year after restarting phosphate application, and had greater residual activity. Keywords fertiliser, withholding, cessation, phosphate, superphosphate, hill country, pastures, soil fertility, wool, sheep

Long term effects of withholding phosphate application on North Island hill country: Economics

1990 ◽  
pp. 29-33
Author(s):  
D.A. Clark ◽  
S.F. Ledgard ◽  
M.G. Lambert ◽  
M.B. O'Connor ◽  
A.G. Gillingham
Keyword(s):  
Cash Flows ◽  
Cost Ratio ◽  
Long Term Effects ◽  
Pasture Production ◽  
Soil P ◽  
Hill Country ◽  
Fertiliser Application ◽  
Positive Cash Flow ◽  
Sustainable Productivity

Results from fertiliser cessation experiments at Ballantrae, Te Kuiti and Whatawhata, on yellow-brown earths, were used to evaluate the fertiliser cessation compared to continued application on hill country breeding ewe systems. At Balhmtrae, on farmlets previously receiving 125 kg superphosphate/ha/yr, continued fertiliser application generated a positive cash flow after 8 years. On farmIets previously receiving rates of 200-375 kg superphosphate/ha/yr positive cash flows were generated by continued fertiliser application after 4, 5 and 6 years at Te Kuiti, Whatawhata and Ballantrae respectively. Fertiliser cessation is a sound strategy to survive periods of low product price:fertiIiser cost ratio. However, it will decrease sustainable productivity and hence farm resale value. Fertiliser recommendations cannot remain constant over time but must consider: animal enterprise, product and fertiliser price, soil P status, and level of pasture utilisation. Keywords fertiliser cessation, superphosphate, Olsen P, economics, hill country, pasture production

Long-Term Effects of Early Pruning and Thinning Treatments on Growth of Natural Longleaf Pine

1980 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Robert C. Sparks ◽  
Norwin E. Linnartz ◽  
Harold E. Harris
Keyword(s):  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Diameter Growth ◽  
Stocking Rate ◽  
Long Term Effects ◽  
Natural Stand ◽  
Stocking Rates ◽  
Pruning Intensity

Abstract Pruning and thinning a young natural stand of longleaf pine (Pinus palustris Mill.) in southwest Louisiana had little influence on height. However, diameter growth was reduced substantially as pruning intensity or stocking rate increased up to 25-percent live crown and 200 stems per acre, respectively. Improved diameter growth at lower stocking rates was not sufficient to equal the total basal area increment of 200 trees per acre.

scholarly journals Building a solid foundation for pasture production in Northland: P, K, S and lime requirements

1995 ◽  
pp. 119-125
Author(s):  
A.H.C. Roberts ◽  
J.D. Morton ◽  
M.B. O'Connor ◽  
D.C. Edmeades
Keyword(s):  
Volcanic Rocks ◽  
Capital Requirements ◽  
Soil Test ◽  
Nutrient Requirements ◽  
Volcanic Soils ◽  
Pasture Production ◽  
Olsen P ◽  
Solid Foundation ◽  
The Relationship ◽  
Soil Groups

The generally strongly weathered, leached soils of Northland consist of four major soil groups. The yellow-brown earths and podzols and yellow brown sands are formed from sedimentary rocks, while brown granular clays and red and brown loams are formed from volcanic rocks. In terms of the relationship between pasture production and fertiliser nutrient requirements, for both sedimentary and volcanic soils, the production functions are shown to be of the "diminishing returns" type, and the point at which near-maximum production (97%) occurs is defined as the "biological optimum" soil test level. Biological optimum test values for sedimentary and volcanic soils are: Olsen P 20 and 22; quicktest K 6 and 7; sulphate-S 10; organic-S 15; and pH 5.9. Once biological optimum soil test levels have been attained then maintenance fertiliser nutrient rates are appropriate. In order to move up the pasture production curve an average of 7 and 11 kg P/ha above maintenance will increase Olsen P by 1 unit for Northland sedimentary and volcanic soils respectively. Similarly, on average 60 kg K/ha will raise quicktest K by 1 unit on volcanic soils, but capital requirements for K on sedimentary soils in Northland are not known. An average of 35 and 25 kg S/ha will correct S deficiencies on sedimentary and volcanic soils. Keywords: biological optimum, lime, Northland, nutrient requirements, phosphorus, potassium, sedimentary soils, sulphur, volcanic soils

scholarly journals Fertiliser requirements for peat soils in the Waikato region

2001 ◽  
pp. 47-51 ◽  
Author(s):  
M.B. O'Connor ◽  
R.D. Longhurst ◽  
T.J.M. Johnston ◽  
F.N. Portegys
Keyword(s):  
Storage Capacity ◽  
Peat Soil ◽  
Soil Nutrient ◽  
Field Trials ◽  
Soil Test ◽  
Nutrient Deficiencies ◽  
Peat Soils ◽  
Pasture Production ◽  
Olsen P ◽  
Productive Land

Peat soils cover approximately 94 000 ha of productive land in the Waikato and are an important soil resource for the region. Much of the research on peats in the 1950s-60s concentrated on the development of raw peats and later in the 1970s on nutrient deficiencies such as copper and selenium. Little to no work was undertaken on soil fertility/soil nutrient relationships of developed peat soils. In 1996, a series of eight field trials was established across a range of developed peat soils in the Waikato to investigate such relationships. The trials continued for 3 years. Results showed that the optimum Olsen P soil test for sustaining near maximum pasture production was 35-45, that K soil tests were of limited use on well developed peats and that winter leaching of S was likely to be important. The Anion Storage Capacity (ASC) test was found to be a valuable tool in indicating the degree of development of peat and in turn allowing interpretation of fertiliser responses. From these introductory investigations of nutrient requirements on peat soils some guidelines and recommendations are presented. Keywords: anion storage capacity (ASC), Olsen P, pasture production, peat, soil test

Changes in soil phosphorus availability and potential phosphorus loss following cessation of phosphorus fertiliser inputs

Soil Research ◽  
2013 ◽  
Vol 51 (5) ◽  
pp. 427 ◽  
Author(s):  
R. J. Dodd ◽  
R. W. McDowell ◽  
L. M. Condron
Keyword(s):  
Agricultural Soils ◽  
Soil Phosphorus ◽  
Pasture Production ◽  
Soil P ◽  
Olsen P ◽  
P Loss ◽  
P Concentration ◽  
Rate Of Decline ◽  
P Retention

Long-term application of phosphorus (P) fertilisers to agricultural soils can lead to in the accumulation of P in soil. Determining the rate of decline in soil P following the cessation of P fertiliser inputs is critical to evaluating the potential for reducing P loss to surface waters. The aim of this study was to use isotope exchange kinetics to investigate the rate of decline in soil P pools and the distribution of P within these pools in grazed grassland soils following a halt to P fertiliser application. Soils were sourced from three long-term grassland trials in New Zealand, two of which were managed as sheep-grazed pasture and one where the grass was regularly cut and removed. There was no significant change in total soil P over the duration of each trial between any of the treatments, although there was a significant decrease in total inorganic P on two of the sites accompanied by an increase in the organic P pool, suggesting that over time P was becoming occluded within organic matter, reducing the plant availability. An equation was generated using the soil-P concentration exchangeable within 1 min (E1 min) and P retention of the soil to predict the time it would take for the water-extractable P (WEP) concentration to decline to a target value protective of water quality. This was compared with a similar equation generated in the previous study, which used the initial Olsen-P concentration and P retention as a predictor. The use of E1 min in place of Olsen-P did not greatly improve the fit of the model, and we suggest that the use of Olsen-P is sufficient to predict the rate of decline in WEP. Conversely, pasture production data, available for one of the trial sites, suggest that E1 min may be a better predictor of dry matter yield than Olsen-P.

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